87, 89, 91 ???

I run 91 cause its ethanol free

 

If that is the case, then it will actually get you better mileage - but not because of the octane. More ethanol content = worse mileage.

In most places, 89 is nothing more than a 50/50 mix of 87 and 91. Most gas stations don't actually have a tank of 89 underground, it is mixed in the pump.

 

Yeah , I never said it was better because of the octane rating , I buy it because its ethanol free

 

Gotcha - I was just throwing that out there before someone else tried the same thing and then thought that it was the octane giving them better mileage.

 

Different manufactures have different philosophies about tuning and the kind of tuning their market is seeking. Ford has their Ecoboost and others do it differently.

In most cases ECU will work with the O2 sensor to determine A/F, but if equipped with additional sensors, an ECU can incorporate those readings into its A/F calculations on the fly.

The truth is you don't really know what the ECU is doing until you tap into it. Although most ECU's are generally the same on a hardware and software level, each is 'tuned' for a specific motor / vehicle and in racing customized for specific tracks and climates.

If you think you know engine tuning, check out the software by AEM.. and then check out Magnetti Marrelli.

http://aemelectronics.com/products/...oducts/programmable-engine-management-systems

http://www.magnetimarelli.com/business_areas/motorsport/software/overview

The ECU maps I've seen in consumer vehicles are a cake walk by comparison.

 

Just out of pure curiosity, do you make the grand announcement and then go through the process of adding peeps to your ignore list, which no doubt is longer then War and Peace. Or, do you add to your list then make the grand announcement?

Ive been elected by unanimous decision to ask this very important question.

...Now back to our regularly scheduled thread.

 

Irrelevant to this thread but nice new avatar pic lol

 

I'll be working on a new avatar once I have some free time for Rock Lobster...

I'm currently lobbying a mod to alter his user name to cock lobster so the modified pic is a more fitting avatar.

 

Sack is a liar...

 

These mods are just overpaid, underworked, greedy TW members who make a Martin Shkreli look like Mother Teresa. They'll take the bribe.

 

No homo (or very little) but, I love you guys for this!

 

I've been playing around with this for a few weeks. The only thing I've noticed is that 87 gets me about 18mpg while 93 gets me about 22mpg. If I mix it half and half (89 octane) I get about 21 or so. I see little to no difference in performance. I suspect that is entirely due to the ecu adjusting the timing. Currently, 87 costs about 1.64/gal and 93 costs 2.04/gal. With 89 at 1.75/gal and giving 15% more fuel economy, that is your best choice. While this is not scientific by any means, I am an engineer with many decades of experience. I'd like to see what others have observed.

 

So slower burning fuel is producing ~20%+ gain in MPG?

This I will need to study...

 

All the stations have the standard "contains up to 10% ethanol".

Please run this experiment for yourself and see.
I have noticed that Costco gas returns poor mpg. Surprisingly, Walmart 93 returns the best mpg.

 

So, I think I understand the effect ethanol has in gasoline engines from an efficiency an corrosive standpoint.

What would be cool is an ethanol % real-time sensor.

Hmmm....maybe that's a good aftermarket gadget. For the entrepreneurial types..there's your first million.


Just fill up with different grades, check your tank average fuel economy and post up

 

I've been noticing the similar results. With 87 I get 18.6, with 92 I'm getting 19-20mpg. But I'm noticing the engine is slightly smoother with the higher octane.

Someone had posted the technical info on this 3.5 and I noticed the compression is 10:1. Is it me, or does this seem kind of high to run 87?

I'm guessing with the higher octane the knock sensor is not retarding the timing and giving slightly better power?

 

On the "2nd gen" 4.0 1GR V6, if you ran 87 you got 236 HP, 266 TQ - if you ran 91, you got 239 HP, 278 TQ (per Toyota specs) with better mileage and a smoother, quieter engine. I have personally noticed this on my own truck. I've had the truck since 60,000 miles (2007 V6 Double Cab). I have run supreme (91 octane) since I got it up until recently. Something happened at the pump where the 91 wasn't working, I had already gone through the payment process on the pump so I said what the hay, I'll try some 87 as I needed gas. Noticeable loss in "refinement" of how the engine ran, the engine was a bit noisier and felt like it lost some power. After filling it back up to 91 the next fill up I noticed the smoothness and power came back to what I was use to. It even mentions in the owners manual that if you run higher octane gas the engine will perform better on this engine. https://en.wikipedia.org/wiki/Toyota_GR_engine

Where I'm getting at is I can not see why Toyota, in it's latest variant of this 3.5 V6 would not incorporate the technology to benefit from higher octane gas (e.g. knock sensor, can adjust the spark timing slightly to suit, etc.). It would have to, to accommodate varying fuel qualities to protect the engine from detonation. Especially when this newer 3.5 V6 engine has a much higher more potent compression ratio (11.8 to 1) over the previous V6 engines used in the Tacoma where ignition timing to use/work with lower octane gas with higher compression ratios is more important to reducing or eliminating detonation or pinging that would cause engine damage. The higher compression ratio, the more the benefit the engine can derive from higher octane gas. You should at least try a few tanks of 91+ octane to see how it does. That, and the fact that higher octane gas typically do not have as much ethanol (depending on your locality) is another reason. And don't run the sh*t stuff - we get Chevron 91 up here in Canada but whenever I ventured south of the border into Washington I found my truck ran even better on the Chevron 92.

 

87

 

Wow what a well developed response